Unicode Characters and Alternative Glyphs

Unicode defines thousands of characters. Some “characters” are surprising, and others are obvious. When I look at the Unicode standard and consider the lengthy debates that occur when deciding upon whether a character should be included, I can imagine the discussion and rationalization that occurs. Deciding on including a character can be difficult.

One of the more difficult concepts for me to appreciate is the difference between light and dark (or black and white) characters. A real example will help me explain this. Consider the “smiley face” characters U+263A and U+263B: ☺ and ☻. These characters are named WHITE SMILING FACE and BLACK SMILING FACE respectively.

These are not the only characters that have white and black options. Dozens of others exist. There are even white and black options for BLACK TELEPHONE and WHITE TELEPHONE.

Of course, once these characters go into the standard, they should stay. One shouldn’t remove existing characters. However, a serious question does arise when considering WHITE and BLACK options for a character.

The question I have is this: Why? Why isn’t the white and black color variation simply a font variation for the same character. The Unicode standard clearly states that it avoids encoding glyph variations of the same character. That makes a lot of sense. However, in practice, the standard at least appears to do exactly the opposite for many characters. I can only guess that someone on the standards committee made a very good, logical and well-supported argument for the character differentiation.

My hope for future versions of the standard is that these kind of color variations will be avoided. Not being on the committee when these characters were added, I cannot really complain. And I hope that my comments here don’t come across that way. However, in the future, I’d like the standard to include annotations for these characters that describe why they deserve separate code points. It certainly isn’t clear from the existing character’s notes, and I’m sure that others would be curious about the reasons as well.